COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/mip_glpk.cc @ 2217:4a10a45d55f6

Last change on this file since 2217:4a10a45d55f6 was 2213:2c094dfa176d, checked in by athos, 13 years ago

Some corrections.

File size: 2.7 KB
Line 
1/* -*- C++ -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2006
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
8 *
9 * Permission to use, modify and distribute this software is granted
10 * provided that this copyright notice appears in all copies. For
11 * precise terms see the accompanying LICENSE file.
12 *
13 * This software is provided "AS IS" with no warranty of any kind,
14 * express or implied, and with no claim as to its suitability for any
15 * purpose.
16 *
17 */
18
19#ifndef LEMON_ILP_GLPK_CC
20#define LEMON_ILP_GLPK_CC
21
22///\file
23///\brief Implementation of the LEMON-GLPK lp solver interface.
24
25#include <lemon/mip_glpk.h>
26
27namespace lemon {
28 
29  MipGlpk::MipGlpk() {
30    lpx_set_class(lp,LPX_MIP);
31  }
32
33  void MipGlpk::_colType(int i, MipGlpk::ColTypes col_type){
34    switch (col_type){
35      case INTEGER:
36        lpx_set_col_kind(lp,i,LPX_IV);
37        break;
38      case REAL:
39        lpx_set_col_kind(lp,i,LPX_CV);
40        break;
41    default:;
42        //FIXME problem
43    }
44  }
45 
46  MipGlpk::ColTypes MipGlpk::_colType(int i){
47    switch (lpx_get_col_kind(lp,i)){
48    case LPX_IV:
49      return INTEGER;//Or binary
50    case LPX_CV:
51      return REAL;
52    default:
53      return REAL;//Error!
54    }
55   
56  }
57 
58  LpGlpk::SolveExitStatus MipGlpk::_solve(){
59    int result = lpx_simplex(lp);
60    //
61    if (lpx_get_status(lp)==LPX_OPT){
62      //Maybe we could try the routine lpx_intopt(lp), a revised
63      //version of lpx_integer
64      result = lpx_integer(lp);
65      switch (result){
66      case LPX_E_OK:
67        return SOLVED;
68      default:
69        return UNSOLVED;
70      }
71     
72    }
73    return UNSOLVED;
74  }
75
76
77  LpGlpk::SolutionStatus MipGlpk::_getMipStatus(){
78
79    if (lpx_get_status(lp)==LPX_OPT){
80      //Meg kell nezni: ha az LP is infinite, akkor ez is, ha az is
81      //infeasible, akkor ez is, de ez lehet maskepp is infeasible.
82      int stat=  lpx_mip_status(lp);
83     
84      switch (stat) {
85      case LPX_I_UNDEF://Undefined (no solve has been run yet)
86        return UNDEFINED;
87      case LPX_I_NOFEAS://There is no feasible integral solution
88        return INFEASIBLE;
89        //     case LPX_UNBND://Unbounded
90        //       return INFINITE;
91      case LPX_I_FEAS://Feasible
92        return FEASIBLE;
93      case LPX_I_OPT://Feasible
94        return OPTIMAL;
95      default:
96      return UNDEFINED; //to avoid gcc warning
97      //FIXME error
98      }
99    }
100    else
101      return UNDEFINED; //Maybe we could refine this: what does the LP
102                        //relaxation look like
103     
104  } 
105
106  MipGlpk::Value MipGlpk::_getPrimal(int i){
107    return lpx_mip_col_val(lp,i);
108  }
109 
110  MipGlpk::Value MipGlpk::_getPrimalValue(){
111    return lpx_mip_obj_val(lp);
112  }
113} //END OG NAMESPACE LEMON
114
115#endif
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